y = 4sin(x-90)+3

Question

Calculate interval of increase, interval of decrease, intercepts

Answer 1

well, you know that sin(x) increases on (-90,90) and decreases on (90,270)

So, this one increases where

-90 < x-90 < 90
0 < x < 180

and decreases where
90 < x-90 < 270
180 < x < 360

and of course y=0 when
sin(x-90) = -3/4

graph is at

http://www.wolframalpha.com/input/?i=4sin(pi%2F180+(x-90))%2B3